Process for obtaining transparent effects on regenerated cellulose fibers



Patented May 2, 1950 PROCESS FOR OBTAINING TRANSPARENT EFFECTS ONREGENERATED GELLULOSE FIBERS Paul Walter Steinlin, Basel, Switzerland,assignor to Aktiengesellschaft Cilander, Herisau, Switzerland NoDrawing. Application July 31, 1946, Serial No. 687,507. In SwitzerlandApril 22, 1943 Claims.

The present application is in the nature of a continuation in part of myearlier copending application Serial No. 533,788, filed May 2, 1944, nowabandoned.

Transparent fabrics, also known as organdies, have as a rule been madefrom pure cotton materials, in particular muslin, or, more rarely, voileor other fine fabrics, such as cambric, etc. Organdies of especiallyfine quality were made of natural silk.

The process hereafter described relates to the production of .plain orpatterned, smooth or crepe transparent fabrics from materials consistingof staple fibre made from regenerated cellulose alone or of staple madefrom regenerated cellulose fibre and cotton, or of mixed cotton andstaple fibre made from regenerated cellulose.

Various experiments were made in the past to transform textiles of thiskind by the ordinary methods used for cotton fabrics. However, even byvarying and adapting working conditions, such as concentration of acidsand alkaline swelling agents, and the duration of the procedure, itproved impossible to turn out marketable goods. Indeed the materialshitherto produced were horny, brittle and stiifened, and in no waysuited for practical use. The present process, on the contrary, producestransparent fabrics which perfectly satisfy all requirements as toappearance, lustre, softness and durability, and show a high degree oftransparency combined with a remarkable clearness of weave.

By hot alkali is understood a treatment according to the present processwith hot alkali solution of mercerizing strength, at a temperature of 25C. or over, having a duration of 5 seconds or more.

These effects are obtained by subjecting the fabric, eventually afterpreparatory or supplementary treatment with swelling agents, to theaction of strong alkali at room temperature for a short time andthereafter to the action of strong alkali at higher temperature.

The process is suited for fabrics made of pure staple fibre made fromregenerated cellulose, or woven with cotton and staple fibre made fromregenerated cellulose, and also for those woven with mixed staple fibremade from regenerated cellulose and cotton yarn. Naturally materials inwhich any or all of the above combinations are present, either in plainor pattern weave, including of course applications with embroidery orSwiss dotted weave, can also be treated by my process.

It is advantageous to delubricate and bleach the fabric to be processed.Crude fabrics can, however, be treated in the same way. In thisconnection it should be borne in mind that, ac cording to the invention,this process is suitable for use in any phase of ire-treatment.

My process can be used to advantage in combination with treatment byswelling agents. The order and manner in which these treatments areapplied depend on the result desired.

By treatment with strong alkali at room temperature is understood amercerizing treatment with alkali of at least 15 Be. at temperaturesranging from -5 to +25 C. for a duration of 5 seconds or more.

Between the two successive alkaline treatments the fabric may be rinsedand neutralized. Nevertheless, it is not necessary to carry out one orboth .of these measu e By nte p sins rins n or neutralization differentresults are obtained.

It is also possible to dry the fabric between the two alkalinetreatments, or to leave it wet. These two procedures also lead todifferent results.

Patterned as well as plain transparent fabrics can be obtained with thepresent process by applying suitable reserves before the swellingtreatment. For example imago effects can be achieved by printing withpigments, resulting in opaque non-transparent patterns. By this methodit is possible, according to the type of process chosen, to use pigmentcarriers proof against acid and alkaline swelling agents, such as gumsor artificial resins, which result in local opaque effects, ornon-acidproof thickening agents which ,produce stiffened transparentdesigns in which the effect of contrast is due to the pigmentationalone. It is moreover possible to introduce reserves during any phase ofthe transforming process so as to achieve, for example, a transparenteffect and then, by rinsing and subsequent swelling and shrinking,obtain the appearance of crepe. It is also possible to get intermediaryeffects by the imprint of swelling agents and subsequent treatment withhot alkali.

The reserves can even be applied during various phases of the process insuch a way that the transformed material shows untreated and swollen,that is shrunken and transparent areas one next to the other.

It is evident that by printing in colours or by the use of colouredreserves such effects can be obtained in various tints.

Fabrics submitted to the present process can be dyed either before orafter treatment. In this way, according to the method of procedure, themost varied results can be obtained, such as 3 plain transparent, or,according to the different affinity for the dye caused by differentlocal treatment, shaded effects.

My process may be illustrated by means of a single example:

A fabric made from regenerated cellulose staple fibre is singed,bleached and tentered. It

is then treated With NaOH of 30 B. at 20 C.'

for 10 seconds. After being rinsed and neutralized it is subjected to afurther treatment with NaOH of 30 B. at 45 C., after which it is rinsedand neutralized and if required can be bleached, dyed or blued,according to the special efiect desired.

I claim:

1. A multiple step process ,for obtaining transparent efi'ects on afabric consisting predominantly of regenerated cellulose staple fibrecomprising a first step of treating said fabric with caustic soda of theorder of 30 Baum at a temperature of to 25 C. for a period of time ofthe order of 5 to seconds and'a second step comprising treating saidmaterial with caustic soda of the order of 30 Baum at a temperature ofthe order of 45 C. for a period of time of the order of 5 seconds.

2. A multiple step process for obtaining transparent effects on a fabricconsisting predominantly of regenerated cellulose staple fibrecomprising a first step of treating said fabric with caustic soda of theorder of 30 Baum at a temperature of the order of C. for a period oftime of the order of 10 seconds and a second step comprising treatingsaid 'material with caustic soda of the order of Baum at a temperatureof the order of C. for a period of time of the order of 5 seconds.

3. A multiple step process for obtaining trans parent effects on afabric consisting predominantly of regenerated cellulose staple fibrescom prisin a first step of treating said fabric with caustic soda ofmercerizing strength at temperatures of the order of -5 to 25 C. for aperiod of time of the order of 5 to 10 seconds, and a second step oftreating said fabric with caustic soda of mercerizing strength at atemperature of the order of 45C. for a period of time of the order of atleast 5 seconds but not substantially more than 5 seconds.

4. A multiple step process for obtaining transparent efiects on a fabricconsisting predomi--- nantly of regenerated cellulose staple fibrescomprising a first step of treating said fabric with caustic soda ofmercerizin strength at a temperature of 5 to 25 C. for a period of timeof the order of 5 to 10 seconds and neutralizing and rinsing the fabric,and a second step of treating the fabric With hot caustic soda ofmercerizing strength at a temperature of the order of 45 C. for aperiod-0f time of the order of at least 5 secondsbut 5 seconds.

, 5. A multiple step process for obtaining transnot substantially morethan parent effects on a fabric consisting predominantly of regeneratedcellulose staple fibres comprising a first step of treating said fabricwith caustic soda of mercerizing strength at a temperature of -5 to 25C. for a period of time of the order of 5 to 10 seconds and rinsing anddrying said fabric, and a second step of treating the fabric with hotcaustic soda of mercerizing.

strength at a temperature of the order of 45 C.

for a period of time of the order of at least 5,

seconds but not substantially more than 5 seconds.

PAUL WALTER STEINLIN.

REFERENCES CITED The following references are of record in the.

file of this patent:

UNITED STATES PATENTS

1. A MULTIPLE STEP PROCESS FOR OBTAINING TRANSPARENT EFFECTS ON A FABRICCONSISTING PREDOMINANTLY OF REGENERATED CELLULOSE STAPLE FIBRECOMPRISING A FIRST STEP OF TREATING SAID FABRIC WITH CAUSTIC SODA OF THEORDER OF 30* BAUME AT A TEMPERATURE OF -5* TO 25*C. FOR A PERIOD OF TIMEOF THE ORDER OF 5 TO 10 SECONDS AND A SECOND STEP COMPRISING TREATINGSAID MATERIAL WITH CAUSTIC SODA OF THE ORDER OF 30* BAUME AT ATEMPERATURE OF THE ORDER OF 45*C. FOR A PERIOD OF TIME OF THE ORDER OF 5SECONDS.